Document scanner with light focusing device

ABSTRACT

A document scanner with a light focusing device downward formed on a document support panel is disclosed. The document scanner is provided with a chassis including a light source and an image sensing device. A scanning window made of light-transmitting material is formed in an area of the document support panel. A driving roller is arranged in a document feeder for driving a document to be scanned through the scanning window. Light emitted from the light source transmits through the scanning window toward the document and is reflected by the document toward the image sensing device. The document support panel forms a convex projection on a bottom surface thereof. The projection confronts the light source for focusing the light onto the document. Preferably, the projection includes an extended section from the bottom surface of the document support panel and forming a convex end surface confronting the light source. A light collecting rim is further downward formed on the document support panel and around the extended section in a direction toward the light source.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates generally to a document scannerhaving automatic document feeder, and in particular to a documentscanner with a light focusing device downward formed on the top glasspanel of the scanner casing of the document scanner.

[0003] 2. Description of the Prior Art

[0004] Document scanners are widely used to form image based electronicfiles of documents. The document scanners are generally categorized asreflective type and transmissive type. A typical reflective documentscanner comprises a chassis arranged inside a scanner casing. Thechassis comprises a light source projecting light onto a document to bescanned. The light is reflected by the document that is being scannedand received by an image sensing device. The image sensing devicereceives the reflected light and forms an image of the document. Atypical example of the image sensing device is a Charge Coupling Device(CCD). The reflective document scanners are generally employed to scandocument printed on a substrate that is not light transmitting.

[0005] The scanner casing of the document scanner comprises alight-transmitting top glass panel on which the document to be scannedcan be positioned. A non-light-transmitting cover is mounted to thescanner casing for selectively covering the top glass panel. In ascanning operation, the chassis is moved in a predetermined direction ina controlled manner. The light emitting from the light source isprojected onto the document and then reflected back to the image sensingdevice whereby an image of the document is read by the image sensingdevice.

[0006] Some of the document scanners are equipped with a documentfeeder. FIGS. 1-3 of the attached drawings show an example of thedocument scanners that are equipped with a document feeder. As shown inFIGS. 1-3, the document scanner comprises a scanner casing 1 having atop panel 11 partly constituted by a light transmitting top glass panel12. A document feeder 2 is mounted on and covering the top panel 12, aswell as the light transmitting top glass panel 12, of the scanner casing1.

[0007] The document feeder 2 comprises a casing (not labeled) insidewhich a driving roller 21 is rotatably mounted. A document passage 22 isdefined around the roller 21. Inlet and outlet openings I and II aredefined in the casing of the document feeder 2 through which a document3 to be scanned is fed into and out of the document feeder 2. Thedocument 3 that is fed into the document feeder 2 is driven by theroller 21 to move through the passage 22 from the inlet opening I towardthe outlet opening II. The document feeder 2 has a bottom panel 20 inwhich a scanning window 23 is formed.

[0008] Also referring to FIG. 4, the document scanner comprises achassis 13 comprising a light source 14 and an image sensing device 15,such as a Charge Coupling Device (CCD). When the document 3 is fedthrough the document feeder 2, a light 4 emitted from the light source14 is projected onto the document 3 through the light-transmitting topglass panel 12 and the scanning window 23. The light is reflected by thedocument 3 and received by the image sensing device 15. An image of thedocument is thus formed by the image sensing device 15.

[0009] Conventionally, the light-transmitting top glass panel 12 is aflat board having opposite surfaces that are substantially planar. Sucha flat board allows light to transmit therethrough. However, the flatboard is not capable to more effectively focus the light onto thedocument 3 to improve the scanning result. Conventionally, the issue isaddressed by increasing the power of the light source or incorporatingadditional reflectors inside the scanner casing of the document scannerto improve the scanning result. Such solutions, although effective inimproving scanning result, increase costs by either consuming more poweror requiring additional parts.

[0010] It is thus desired to provide a document scanner having lightfocusing device for overcoming the above problems.

SUMMARY OF THE INVENTION

[0011] An object of the present invention is to provide a documentscanner incorporating a light focusing device.

[0012] Another object of the present invention is to provide a documentscanner comprising a convex lens formed on a light-transmitting topglass panel of a scanner casing of the document scanner for effectivelyfocusing light onto a document to be scanned so as to enhance scanningresult of the document scanner.

[0013] A further object of the present invention is to provide adocument scanner comprising a light focusing device that comprises lightcollecting rims for effectively concentrating light emitted from a lightsource toward a document to be scanned so as to enhance scanning resultof the document scanner.

[0014] To achieve the above objects, in accordance with the presentinvention, there is provided a document scanner with a light focusingdevice downward formed on a top glass panel of the scanner casing. Thedocument scanner is provided with a chassis including a light source foremitting a light and an image sensing device. A document feeder providedwith a scanning window is positioned on the top glass panel of thedocument scanner. A driving roller is arranged in the document feederfor driving a document to be scanned through the scanning window. Lightemitted from the light source transmits through the top glass panel ofthe scanner casing and the scanning window of the document feeder towardthe document and is reflected by the document toward the image sensingdevice. The top glass panel forms a convex projection on a bottomsurface thereof. The projection confronts the light source for focusingthe light onto the document. Preferably, the projection includes anextended section from the bottom surface of the top glass panel andforming a convex end surface confronting the light source. A lightcollecting rim is further downward formed on the top glass panel andaround the extended section in a direction toward the light source.

BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The present invention will be apparent to those skilled in theart by reading the following description of preferred embodimentsthereof, with reference to the attached drawings, in which:

[0016]FIG. 1 is a perspective view of a conventional document scannerhaving a document feeder;

[0017]FIG. 2 is a perspective view of the conventional document scanner;

[0018]FIG. 3 is a cross-sectional view of the conventional documentscanner taken along line A-A of FIG. 1;

[0019]FIG. 4 is a schematic view of a portion of the conventionaldocument scanner for illustrating the scanning operation performed bythe conventional document scanner;

[0020]FIG. 5 is a schematic view similar to FIG. 4 but showing a firstembodiment of a document scanner constructed in accordance with thepresent invention;

[0021]FIG. 6 is a schematic view similar to FIG. 5 but showing a secondembodiment of the document scanner constructed in accordance with thepresent invention;

[0022]FIG. 7 is a schematic view similar to FIG. 6 but showing a thirdembodiment of the document scanner constructed in accordance with thepresent invention; and

[0023]FIG. 8 is a schematic view similar to FIG. 5 but showing a fourthembodiment of the document scanner constructed in accordance with thepresent invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] It is to be noted before a description of the preferredembodiments of the present invention is given that a document scannerconstructed in accordance with the present invention has a generalstructure similar to that of a conventional document scanner shown inFIGS. 1-4. Thus, most of the parts of the document scanner that areidentical or corresponding to those of the conventional document scannerwill not be described again hereinafter for simplicity. However, inorder to provide a clear description of the present invention, whennecessary, parts of the conventional document scanner may beincorporated in the following description and such parts will bear thesame reference numerals as shown in FIGS. 1-4 for simplicity of thedescription.

[0025] With reference to the drawings FIGS. 3-5 and in particular toFIG. 5, a document scanner constructed in accordance with a firstembodiment of the present invention comprises a scanner frame or casing1 having a top glass panel 12 that is made of a light-transmittingmaterial to allow light to transmit therethrough and a document feeder 2having a bottom panel 20 selectively positioned on the top glass panel12 of the scanner casing 1. A scanning window 23 is defined in thebottom panel 20 of the document feeder 2. The document feeder 2generally comprises a driving roller 21 for driving a document 3 to bescanned through the scanning window 23.

[0026] A chassis 13 is arranged inside the scanner casing 1 of thedocument scanner. The chassis 13 comprises a light source 14 that isselectively activated to project a light beam 4 through both the topglass panel 12 and the scanning window 23 toward the document 3 and animage sensing device 15, which may be a known Charge Coupling Device(CCD), for receiving the reflected light beam 4 from the document 3.

[0027] In accordance with the present invention, a light focusing device5 is includes in the document scanner of the present invention. Thelight focusing device 5 in the embodiment illustrated comprises aprojection 51 formed on a bottom surface of the top glass panel 12 andconfronting the light source 14. The projection 51 has a convexconfiguration, made as a convex lens for focusing or concentrating thelight 4 from the light source 14 onto the document 3. In a preferredembodiment of the present invention, the projection 51 is integrallyformed with the top glass panel 12. However, it is apparent to thosehaving ordinary skills to make the convex lens separate from the topglass panel 12.

[0028]FIG. 6 shows a second embodiment of the document scanner inaccordance with the present invention. The document scanner of thesecond embodiment is substantially similar to the first embodimentdiscussed with reference to FIG. 5 except that the light focusing device5 further comprises an extended section 52 extending from the bottomsurface of the top glass panel 12 toward the light source 14. Theextended section 52 forms a convex projection 53 confronting the lightsource 14 to function as a convex lens that focuses the light 4 from thelight source 14 onto the document 3. The extended section 52 is madetoward the light source 14 and guiding the light 4 generated by thelight source 14 in a direction toward the document 3.

[0029]FIG. 7 shows a third embodiment of the document scanner inaccordance with the present invention. The third embodiment issubstantially similar to the second embodiment shown in FIG. 6. Thelight focusing device 5 of the third embodiment comprises an extendedsection (not labeled) extending from the bottom surface of the top glasspanel 12 toward the light source 14 and forming a convex end surface 54confronting the light source 14 for focusing and guiding the light 4onto the document 3. A light collecting rim 55 is further downwardformed around the light focusing device 5 for collecting andconcentrating the light 4 generated by the light source 14 in adirection toward the light source 14.

[0030]FIG. 8 shows a fourth embodiment of the document scanner inaccordance with the present invention. The fourth embodiment issubstantially similar to the first embodiment shown in FIG. 5. In thefourth embodiment, a partition or wall 12′ is provided between the lightsource 14 and the document 3 to be scanned. The wall 12′ forms ascanning window 24 made of light-transmitting material through which ascanning light 4 emitted from the light source 14 passes. A lightfocusing device 5 comprising a projection 56 having an arcuate convexconfiguration, made as a convex lens for focusing or concentrating thelight 4 from the light source 14 onto the document 3, is formed on thebottom surface of the scanning window 24. The scanner comprises adriving roller 21 arranged above the scanning window 24 (and thus thewall 12′) and opposite to the light source 14. A document passage (notlabeled) is formed between the roller 21 and the wall 12′ fortransmission of the document 3 therethrough. When the document 3 is sentthrough the passage, the light 4 from the light source 14 is focused andconcentrated by the focusing device 5 onto the document 3 and thenreflected by the document 3 toward a Charge Coupled Device (CCD) 15 forforming an image of the document thereon.

[0031] Although the present invention has been described with referenceto the preferred embodiments thereof, it is apparent to those skilled inthe art that a variety of modifications and changes may be made withoutdeparting from the scope of the present invention which is intended tobe defined by the appended claims.

What is claimed is:
 1. A document scanner comprising: a scanner casing with a top glass panel thereon, defining an inner space; a document feeder having a bottom panel positioned on the top glass panel of the scanner casing, a scanning window being formed on the bottom panel, for feeding a document to be scanned through the scanning window of the bottom panel; a chassis arranged inside the inner space of the scanner casing, the chassis comprising a light source for emitting a light and an image sensing device for receiving a reflection of the light transmitted from the light source; and a light focusing device downward formed on the top glass panel with respective to the light source of the chassis; wherein when the document is fed into the document feeder and moved through the scanning window, the light from the light source is focused by the light focusing device onto the document, the light being reflected by the document back to the image sensing device for forming an image of the document.
 2. The document scanner as claimed in claim 1, wherein the light focusing device comprises a convex projection integrally formed with the top glass panel.
 3. The document scanner as claimed in claim 1, wherein the light focusing device comprises: a downward extended section integrally formed on the top glass panel toward the light source, having a bottom end; and a convex projection integrally formed on the bottom end of the extended section, having a convex end surface confronting the light source.
 4. The document scanner as claimed in claim 1, wherein the light focusing device comprises: a downward extended section integrally formed on the top glass panel toward the light source, having a bottom end; a convex projection integrally formed on the bottom end of the extended section, having a convex end surface confronting the light source; and a light collecting rim downward formed on the top glass panel and around the extended section in a direction toward the light source.
 5. A document scanner comprising: a document support panel having a top surface and a bottom surface; a scanning window made of light-transmitting material and formed in an area of the document support panel; and a light focusing device downward formed on the bottom surface of the document support panel and located in the area of the scanning window, adapted to focus a light emitted from a light source through the scanning window onto a document fed on the top surface of the document support panel and passing through the scanning window.
 6. The document scanner as claimed in claim 5, wherein the light focusing device comprises a convex projection integrally formed with the document support panel.
 7. The document scanner as claimed in claim 5, wherein the light focusing device comprises: a downward extended section integrally formed on the document support panel toward the light source, having a bottom end; and a convex projection integrally formed on the bottom end of the extended section, having a convex end surface confronting the light source.
 8. The document scanner as claimed in claim 7, wherein the light focusing device comprises: a downward extended section integrally formed on the document support panel toward the light source, having a bottom end; a convex projection integrally formed on the bottom end of the extended section, having a convex end surface confronting the light source; and a light collecting rim downward formed on the document support panel and around the extended section in a direction toward the light source. 